A U.S. Army Captain lectures troops at Camp Desert Rock, about protection against heat from an atomic explosion

An Army Captain stands at a blackboard in Camp Desert Rock, Nevada, as he lectures U.S. Army troops about protection against heat from an atomic explosion. The troops are seated in a large outdoor assembly area. Closeups of the soldiers in the audience. He notes that burns from the heat can occur in a half second from the time of the flash. He notes that burning can occur within 3 miles of the explosion, but ordinary clothing can protect as close as 1 mile away. And, the shade of a foxhole will protect from the heat. The Captain also mentions the blinding flash of an atomic explosion. The troops all look up momentarily at the sun, as he compares it to the flash of an atomic explosion.